UK charities' rush to organise headline-grabbing "showpiece" Asia tsunami projects delivered poor quality housing for survivors, experts say.
The report said many tsunami victims were still living in tents
An evaluation for the Disaster and Emergencies Committee also criticised the "relative neglect" of Indonesia.
However, the DEC insisted donations had saved thousands of lives and the report praised charities for extensive relief provision and cultural sensitivity.
The report praised successes in health, sanitation and child protection.
'Lack of expertise'
The report criticised the fact Indonesia received 31% of aid despite suffering an estimated 60% of the damage.
It said many victims of the tsunami were still living in tents, partially due to the agencies' "lack of expertise in post-disaster housing".
"Instead, individual managers have been under pressure or behaved as if they were under pressure, to create showpiece projects that might present positive images when the media arrived around the time of the anniversary," it said.
"This has resulted in some poor quality housing both in terms of construction standards and social acceptability.
"High media profile tends to encourage competition, an opportunistic approach among the agencies and poor co-ordination.
"Agencies distance themselves from intractable issues, such as basic needs in temporary shelters, and compete for what can be done rather than what should be done."
The report, an independent evaluation of the DEC Tsunami response, was commissioned so that committee members could learn about the effectiveness of their work.
The former International Development Secretary, Clare Short, told Newsnight, on Wednesday, that the charities and non-governmental organisations needed to take on board the report's conclusions.
"They follow the cameras," she said.
"Ministers fly in and take up helicopter space and airport space and you get all the NGOs trying to grab headlines rather than co-ordinate and do a good job.
"It's a sort of competition for the limelight to look like good people. And it's really not very good."
However, the chief executive of the British Red Cross, Sir Nick Young - who is on the panel of the DEC - told Newsnight the report had also praised the efforts of the charities.
He said: "We are undertaking an enormous building programme in Indonesia, in the Maldives and in Sri Lanka and in the ten other countries affected - enormous complex issues to do with land ownership, identity of beneficiaries, compliance with government regulations and these take time."
A spokesman for Christian Aid said the charity was "proud of its work helping the survivors of Asian tsunami".
Spokesman Dominic Nutt said Christian Aid worked with partners in the communities affected by the tsunami to ensure they had choices about the sort of aid they needed.
"Our partners all work in consultation with local communities about the rehabilitation they need - rather than imposing aid on them."
The DEC represents the UK's leading humanitarian agencies, including Save the Children, Oxfam, Christian Aid, British Red Cross and Action Aid.
The DEC said in a statement: "Notwithstanding criticisms in the report, much has been achieved in response to what was an unprecedented natural disaster.
"The report confirms that the response by member agencies was 'impressive', including that DEC members achieved higher standards and have shown more good practice than most non-DEC agencies."
It went on: "One year on, over one-third of the money donated to the DEC has been spent. DEC members plan to spend up to £190m in 2006, this will include more than 20,000 permanent houses, which will house around 100,000 men, women and children. A major focus will also be livelihoods.
"The British public should be clear about two things. Firstly that the money they generously gave has been used to save the lives of many thousands and improve the lives of millions, and secondly that the DEC agencies will not shy away from learning and acting on the lessons of this report."